In the field of application concerning osteosynthesis of the spine, there exist numerous osteosynthesis devices, each comprising a connection system connected at either end to fixing portions suitable for being fixed to vertebrae via bone anchoring elements.
A first category of osteosynthesis devices are known which comprise a rigid connection connected at opposite ends to portions for fixing to the vertebrae. Such a rigid stabilization device leads to mechanical stresses being shifted to intervertebral joints adjacent to the joints that have been stabilized.
In order to remedy that problem, a second category of osteosynthesis device is known comprising an elastically deformable connection system connected at opposite ends to portions for fixing to the vertebrae. In general, such a “dynamic” intervertebral stabilization device has a spring or damper type system suitable for withstanding elastically any axial elongation or compression. Such a stabilization device is capable of damping both compression movement and traction movement, thereby allowing vertebral segments to move in physiological manner. Certain known devices are also adapted to damp flexion-extension movements in the antero-posterior plane and also lateral flexing movements.
Nevertheless, known prior solutions are not of simple design and they generally present relatively large bulk which makes it particularly difficult to place such a device in a non-stressed position.